|
Nourseothricin
Nourseothricin (NTC) is a member of the streptothricin-class of aminoglycoside antibiotics produced by ''Streptomyces'' species. Chemically, NTC is a mixture of the related compounds streptothricin C, D, E, and F. NTC inhibits protein synthesis by inducing miscoding. It is used as a selection marker for a wide range of organisms including bacteria, yeast, filamentous fungi, and plant cells. It is not known to have adverse side-effects on positively selected cells, a property cardinal to a selection drug. Streptothricin F is effective against highly drug-resistant gram-negative bacteria, including carbapenem-resistant ''E. coli''. NTC can be inactivated by nourseothricin N-acetyl transferase (NAT) from '' Streptomyces noursei'', an enzyme that acetylates the beta-amino group of the beta-lysine residue of NTC. NAT can thus act as an antibiotic resistance Antimicrobial resistance (AMR or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nourseothricin N-acetyl Transferase
Nourseothricin (NTC) is a member of the streptothricin-class of aminoglycoside antibiotics produced by ''Streptomyces'' species. Chemically, NTC is a mixture of the related compounds streptothricin C, D, E, and F. NTC inhibits protein synthesis by inducing miscoding. It is used as a selection marker for a wide range of organisms including bacteria, yeast, filamentous fungi, and plant cells. It is not known to have adverse side-effects on positively selected cells, a property cardinal to a selection drug. Streptothricin F is effective against highly drug-resistant gram-negative bacteria, including carbapenem-resistant ''E. coli''. NTC can be inactivated by nourseothricin N-acetyl transferase (NAT) from '' Streptomyces noursei'', an enzyme that acetylates the beta-amino group of the beta-lysine residue of NTC. NAT can thus act as an antibiotic resistance Antimicrobial resistance (AMR or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces
''Streptomyces'', from στρεπτός (''streptós''), meaning "twisted", and μύκης (''múkés''), meaning "fungus", is the largest genus of Actinomycetota, and the type genus of the family Streptomycetaceae. Over 700 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, and have very large genomes with high GC content. Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct "earthy" odor that results from production of a volatile metabolite, geosmin. Different strains of the same species may colonize very diverse environments. Streptomycetes are characterised by a complex secondary metabolism. Between 5-23% (average: 12%) of the protein-coding genes of each ''Streptomyces'' species are implicated in secondary metabolism. Streptomycetes produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptothricin
Streptothricins are a group of antibiotics in the aminoglycoside class. The first antibiotic in the group was isolated from '' Streptomyces lavendulae'' in 1942. It was later determined to be a mixture of closely-related compounds, and is now known as nourseothricin. Although initial interest was positive because it appeared to be the first broad-spectrum antibiotic, meaning it was effective against both Gram-positive and Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ... bacteria, it never found clinical use due to toxicity. However, because of the increasing need for new antibiotics due to resistance to existing antibiotics, there is a current interest in developing new drugs based on the chemical scaffold of the streptothricins. References {{reflist Aminoglyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Resistance
Antimicrobial resistance (AMR or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, which are drugs used to treat infections. This resistance affects all classes of microbes, including bacteria (antibiotic resistance), viruses (antiviral resistance), parasites (antiparasitic resistance), and fungi (antifungal resistance). Together, these adaptations fall under the AMR umbrella, posing significant challenges to healthcare worldwide. Misuse and improper management of antimicrobials are primary drivers of this resistance, though it can also occur naturally through genetic mutations and the spread of resistant genes. Antibiotic resistance, a significant AMR subset, enables bacteria to survive antibiotic treatment, complicating infection management and treatment options. Resistance arises through spontaneous mutation, horizontal gene transfer, and increased selective pressure from antibiotic overuse, both in medicine and agriculture, which accelerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylation
: In chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed ''acetate esters'' or simply ''acetates''. Deacetylation is the opposite reaction, the removal of an acetyl group from a chemical compound. Acetylation/deacetylation in biology Histone deacetylases "play crucial roles in gene transcription and most likely in all eukaryotic biological processes that involve chromatin". Acetylation is one type of post-translational modification of proteins. The acetylation of the ε-amino group of lysine, which is common, converts a charged side chain to a neutral one. Acetylation/deacetylation of histones also plays a role in gene expression and cancer. These modifications are effected by enzymes called histone acetyltransferases (HATs) and histone deacetylases (HDACs). Two general mechanisms are known for deacetylation. One mechanism involves zinc binding to the acetyl o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces Noursei
''Streptomyces noursei'' is a bacterium species in the genus ''Streptomyces''. Uses Nystatin Nystatin, sold under the brand name Mycostatin among others, is an antifungal medication. It is used to treat ''Candida (fungus), Candida'' infections of the skin including diaper rash, Candidiasis, thrush, esophageal candidiasis, and vaginal ... is a polyene antifungal medication isolated from ''S. noursei''. References External links ''Streptomyces noursei'' on Encyclopedia of Life noursei Bacteria de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Cell
Plant cells are the cells present in Viridiplantae, green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of Flagellum, flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells. Characteristics of plant cells * Plant cells have cell walls composed of cellulose, hemicelluloses, and pectin and constructed outside the cell membrane. Their composition contrasts with the cell walls of fungus, fungi, which are made of chitin, of bacteria, which are made of peptidoglycan and of archaea, which are made of pseudopeptidoglycan. In many cases lignin or suberin are secreted by the protoplast as secondary wall laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbapenem
Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibiotic ..., carbapenems are members of the beta-lactam antibiotics drug class, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams. Carbapenem antibiotics were originall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminoglycoside Antibiotics
Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside (sugar). The term can also refer more generally to any organic molecule that contains amino sugar substructures. Aminoglycoside antibiotics display bactericidal activity against Gram-negative aerobes and some anaerobic bacilli where resistance has not yet arisen but generally not against Gram-positive and anaerobic Gram-negative bacteria.ME Levison, MD, 2012, Aminoglycosides, The Merck Manua accessed 22 February 2014. Streptomycin is the first-in-class aminoglycoside antibiotic. It is derived from ''Streptomyces griseus'' and is the earliest modern agent used against tuberculosis. Streptomycin lacks the common 2-deoxystreptamine moiety (image right, below) present in most other members of this class. Other examples of aminoglycosides include the deoxystreptamine-containin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filamentous Fungi
A mold () or mould () is one of the structures that certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form mushrooms; others grow as single cells and are called microfungi (for example yeasts). A large and taxonomically diverse number of fungal species form molds. The growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism. The hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls (septa) may delimit connected compartments along the hyphae, each containing one or multiple, genetically identical nuclei. The dusty texture of many molds is caused by profuse production of asexual spores (conidia) formed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
